AU701692B2 - Apparatus for manufacturing containers by blow moulding plastic preforms - Google Patents

Description

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AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION NAME OF APPLICANT(S): SIDEL S.A.

ADDRESS FOR SERVICE: DAVIES COLLISON CAVE Patent Attorneys I Little Collins Street, Melbourne, 3000.

INVENTION TITLE: Apparatus for manufacturing containers by blow moulding plastic preforms The following statement is a full description of this invention, including the best method of performing it known to me/us:-

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r i 1A- APPARATUS FOR MANUFACTURING CONTAINERS BY BLOW MOULDING PLASTIC PREFORMS The present invention relates to apparatus of the manufacture of containers such as bottles, pots, or any other type of hollow body, by thermal conditioning followed by blow moulding of plastic preforms.

It applies in particular to the manufacture of containers in polyethylene terephthalate (PET), s obtained by kiraw-moulding of preforms after they are subjected to appropriate thermal conditioning..

Known manufacturing plants for blow moulding of preforms comprise a station for thermal conditioning of preforms, where the preforms are brought to a temperature at which they can then be deformed by blow moulding, a station supplying preforms to this conditioning station, a blow moulding station having moulds whose recess exhibits the finished external form of the container to be produced, and a transfer station for preforms between the thermal conditioning station and the blow moulding station.

S: For the majority of materials, and particularly PET, it is preferred to draw the preform in a controlled manner and concomitant with blow moulding. In this case, the blow moulding station is is replaced by a drawing blow moulding station, simultaneously comprising drawing m n;c~ such as an extension rod which embosses the floor of the preform in a controlled manner during blow moulding.

In the following description, the term blow moulding applies equally to pure blow mouldinf or to drawing blow moulding.

2 "ib Various types of manufacturing plants already exist. In a known type of plant the blow moulding station is constituted by a device mounted to rotate around a vertical axis. By virtue of its circular movement, this device, known as blow moulding wheel or carousel, comprises at least two identical moulds, each having a moulding cavity, distributed symmetrically and regularly Srelative to the axis of rotation and each borne by a die support device.

Consequently, if there are two moulds, they are diametrically opposed; more generally, they are offset at an angle A determined by the following equation: A 3 60/n, in which n is the i r number of moulds.

P:\OPER\PHH\13446-95.180 -7/7/98 -2- Each mould is a portfolio mould formed from two half moulds articulated around a vertical axle supported by the carousel such that the moulds open like a wallet, along a radial symmetry plane passing through the axis of revolution of the carousel and through the axis of articulation of the half moulds; they open radially outwardly.

It is known for these plants to produce high cycle rates; therefore, with materials such as PET and the current thermal conditioning processes, as many as 1100 containers can be manufactured per hour utilising drawing blow moulding, with the overall capacity of the plant depending on the number of moulds supported by the carousel. By way of example, the largest plants currently being operated by the applicant carry 40 moulds. t| In plants of this type drive means associated with the thermal conditioning station comprises supports, each of which is adapted to receive and grip a preform, firmly though removably, and which are engaged together to constitute an endless device. The endless •0.0 15 device may be constituted by a carousel or, for example, by a chain extending between at least two support wheels. Each support may be in the form of a mandrel with an elastic ring and introduced into the openings of the preform. Furthermore, the supports are driven into the thermal conditioning station such that the preform can be heated there with the opening the neck facing downwards to avoid any deformation, by convection, of this opening during thermal conditioning. In effect, the opening of the preform corresponds already to that of the finished container.

Moreover, known plants are preferably equipped in such a way that after thermal conditioning the preforms are turned over so that their opening is uppermost, so that they are not deformed under their own weight and because of their softness prior to blow moulding of the containers. In this case, they can be turned upright in the thermal conditioning device, or in the transfer station.

A major drawback to these plants is that they are usually built around a basic r sRA430 mechanical and hydraulic structure (carousel, motors, die supports, and the like) of such a -t t'i U -L 7 P:\OPER\PHH\13446-95.18U 7/7/98 -3size to enable those containers to be manufactured which are of significant size or volume and/or which require for their blow moulding certain parameters especially pressure of increased value. Customisation is then carried out at the request of the user of the plant, which consists of, amongst others, providing the plant with moulds, each of which has a cavity adapted to the containers to be produced, and controlling the moulding and thermal conditioning parameters as a function of the preforms used and the desired finished containers.

If the containers to be produced are small in size or require only slight blow moulding pressure, the plant can appear to be oversize relative to these containers.

According to the present invention there is provided apparatus for the production of containers by blow moulding preforms, comprising at least two portfolio moulds arranged on the periphery of a blow moulding carousel, each of the moulds having at least two moulding 15 cavities whose longitudinal axes are spaced apart by a first distance, wherein the apparatus further includes drive means for transporting and holding the performs on a path along which thermal conditioning means is disposed and in which the spacing between the longitudinal axes of adjacent preforms is a second distance less than the first distance, means for transferring the preforms to a mould, and means for modifying the spacing of the preforms between the drive means and the mould.

A particular advantage of the invention is that it enables the characteristics of the plant to be exploited best. In particular, if it is calculated that at each cycle of ine mould a plant can produce in each mould a single container having a maximum determined volume, the invention allows customisation of the plant so that several containers of smaller volume are produced in each mould at each cycle, due to several cavities in each mould. i Another advantage of the present invention is that it enables an increase especially of the production cycles, since the overall number of moulding cavities is increased.

rl f P\OPER\PHH\13446-95.180- 7/iS -4- Furthermore, by the arrangement of the invention, the preforms can be very close to each other in the thermal conditioning means such that the latter can be as compact as possible, considering the desired production rate of the apparatus and the preforms can be separated prior to being introduced into the mould according to the spacing of the mould cavities.

A minimum for the first distance may be calculated based on the radial expansion of the preforms during the blow-moulding operation, and a thickness of material to be left between said at least two moulding cavities sufficient to ensure that the mold has the proper mechanical strength during the blow moulding operation.

In one embodiment the spacing modifying means comprises means for unloading each preform from the drive means, and the means for transferring transfers adjacent preforms from the spacing modifying means to a predetermined position of the at least two moulding cavities. The means for transferring advantageously comprises first preform-transfer means 4 for gripping adjacent preforms on the spacing modifying means and for placing them in the at least two moulding cavities.

#4 In the one embodiment of the spacing modifying means preferable comprises a 44 0 rotatable plate incorporating alternating fixed and movable means for receiving the preforms.

The final and movable means advantageously comprise notches for receiving the preforms, 1 in which case the apparatus conveniently further includes a curved guide allowing the preforms to be carried by the rotating plate between the notches and the curved guide from when they are unloaded from the drive means to when they are received by the means for transferring. The rotary table may be circular with the final notches spaced evenly short of the periphery of the plate and made directly in the mass of the plate.

Conveniently the movable notches are formed in identical elements which are mounted rotatably on the plate and means is provided whereby, at any time, the position of any one t S RA4 of the movable elements relative to the fixed notches on either side thereof is dependent on 1..

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P:\OPER\PHH\13446.95. 180 7/98 the angular position of the rotatable plate. Preferably, the rotatable plate comprises sectors which are spaced evenly apart and which define identical radially extending recesses each accommodated in a space between two adjacent fixed notches, the movable elements being located in the recesses such that the fixed and movable notches transport the preforms at the same level. Preferably also, the axes of rotation of the movable elements are spaced evenly around the rotatable plate and delimit a circle concentric to the axis of rotation of the plate.

Each movable element may be connected to a respective crank to ensure its rotation and thus the changing of the spacing, with a first end of each crank connected to a respective movable element being rotatably connected with a rotatable axle of the movable element and a second end being engaged in a guide cam provided in the spacing modifying means. The guide cam may be constituted by a groove forming a closed loop in a stationary plate disposed around a drive shaft of the rotatable plate in a plane parallel to the latter, the groove having i variations in its radius of curvature such that when the rotatable plate is rotated, the second 15 end of each crank follows the variations of the curvature of the groove, actuating rotation of the associated crank and thus a variation in the clearance.

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In the one embodiment, the first preform-transfer means may comprise at least one first arm of which a first end carries the same number of means for gripping the preforms, such as pairs of pincers, as each mould has moulding cavities, the spacing between the centres of adjacent gripping means being identical to the first distance.

Conveniently, the apparatus includes second transfer means for unloading the containers from the moulds. The second transfer means may comprise at least one second arm of which a first end carries the same number of means for gripping the containers, such as pairs of pincers, as each mould has moulding cavities, the spacing between the centres of adjacent gripping means being identical to the first distance.

The aforementioned gripping means for the preforms are conveniently carried by a -j 4 30 first support rotatably mounted on the first end of the first arm of the first preform-transfer 1~ P:\OPER\PHH\13446-95,180 -7198 -0means and/or the aforementioned gripping means for the containers are conveniently carried by a second support rotatably mounted on a first end of the second arm of the second transfer means.

Advantageously, a second end of the first arm is mounted on a third support rotatable about an axis parallel to that of the carousel carrying the moulds and/or a second end of the second arm is mounted on a fourth support rotatable about an axis parallel to that of the carousel carrying the moulds, and means is provided for the first and/or second arm to perform movements of rotation and translation relative to the respective third or fourth rotatable support. Conveniently the movements of rotation and translation of the first support of the gripping means for the preforms and/or of the second support of the gripping means for the containers, at the first end of the first and/or second arm, respectively, are controlled by means connected with the respective third and fourth rotatable support. Preferably, the

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means for the first and/or second arm to perform the movements of rotation and translation S 15 relative to the respective third or fourth rotatable support and/or the means for the first or second rotatable support of each gripping means to perform the movements of rotation and translation relative to its respective arm comprise cams carried by the respective third or fourth rotatable support and acting on complementary elements, such as rollers and connecting rods, connected with the respective arm.

S Wherein the one embodiment the spacing modifying means comprises a rotatable plate incorporating alternating fixed and movable means for receiving the preforms, the drive means associated with the thermal conditioning means may compromise an endless chain of preform support devices extending between two wheels. In this arrangement, the rotary table conveniently is arranged below one of the wheels with parallel axes of rotation, is driven therewith, and is adapted to be used to support the preforms while they are engaged with the preform support devices and/or between the unloading of the preforms from the drive means and the engagement of the preforms by the means for transferring. Preferably, the spacing .t ~modifying means are arranged so that the fixed and movable means for holding the preforms ,30 are spaced by thesecond distance when they are in a zone for engaging the preforms with the IT A a

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P:\OPER\PII*\13446-951.SO .7/98 -7preform support devices and/or when they are in a zone for unloading the preforms from the drive means.

Alternatively, the thermal conditioning means may be part-circular in which case the drive means associated therewith conveniently comprises an array of preform support devices carried by a carousel with the rotatable plate of the spacing-modifying means disposed at the periphery of the carousel so as to engage and support the preforms after they are unloaded from the drive means and until they are engaged by the means for transferring. A Various embodiments of apparatus according to the invention will now be described by way of example only with reference to the accompanying diagrams, in which: i Figure 1 is a skeleton diagram of one embodiment of the apparatus; Figure 2 is a plan view of the preferred embodiment of mechanisms of the apparatus for changing the spacing of the preforms, for transferring the preforms into the 15 moulds, and for unloading the containers from the moulds; Figure 3 is a view through section AA of Figure 2 of the spacing modifying means; r Figure 4 is a preferred lay-out view of the elements of Figures 2 and 3 in apparatus having a linear thermal conditioning device; Figure 5 is a possible lay-out view of'the elements of Figures 2 and 3 in apparatus having a part-circular thermal conditioning device.

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According to the embodiment illustrated in Figures 1 to 5, the present invention relates to a plant for manufacturing containers by blow moulding of plastic preforms 1, the latter being produced by injection moulding in an injection moulding machine.

With reference to Figure 1, the preforms thus produced are supplied by one or more storage containers (not illustrated) by a supply device 2 such as a chute, to a thermal conditioning device 3 such as an infrared radiation furnace, where they are heated to the required temperature for blow moulding. In a known manner drive means for conditioning 30 device 3 is constituted by an endless chain 31 with rotatable support devices or reels evenly P:\OPER\PHH\3446-95.180 -7/7/98 -8spaced at a pitch of P1 and each designed to take up a preform; the device 3 comprises one or more zones 32 having infrared heating means (not illustrated), in which the preforms are exposed to heating during circulation of the endless chain.

To prevent softening of the necks of the preforms thermal conditioning device 3 preferably comprises means for rotating the reels to enable each of the preforms, after they have been loaded with their opening uppermost, to be each carried throughout the entire thermal treatment with their opening facing downwards and their base facing upwards. The introduction of each preform with its opening facing upwards is ensured by a flange located beneath their opening, enabling it to be supported in slide rails 21, 22 of supply device 2, Next, before it encounters a first heating zone 32, each preform is attached firmly to a reel by engaging its neck with known elements such as a mandrel and an elastic ring each S' belonging to the respective reel, then upturned so that the opening now faces downwards.

15 After undergoing thermal treatment and after the opening has been returned upwards, each preform is separated from the reel carrying it by stripping, that is, withdrawal of the mandrel and the elastic ring from its neck, before being transferred to a blow moulding station or device 4 by means of an interface device 5 which will be described in greater detail hereinbelow. Following blow moulding, the containers thus produced are removed by an 20 appropriate device not illustrated in the skeleton diagram and placed at the site of arrow

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Blow moulding station 4 is constituted by a revolving carousel or platen 40 carrying at least two moulds 41, 42, 43, 44 of the wallet type, distributed symmetrically and evenly around vertical axis of rotation 45 of the carousel, each comprising at least two moulding cavities.

Each mould 41, 42, 43, 44 is formed out of two half moulds 46A, 46B, articulated to open and close by means of known elements (not illustraLtd) round an axle 47 borne on the A carousel. By way of non-limiing example, opening and closing of the moulds can be ensured P:\OPER\PIH\13446-95.180- 7/7/98 -9by means which are identical or equivalent to those described in the French patent published under number 2 479 077, incorporated herein by reference, that is, by a mechanism comprising a journal arm in carousel 40 and controlled by a roller cooperating with a fixed cam relative to the carousel.

Each half mould comprises as many half cavities as the mould itself has cavities. In the example illustrated where each mould comprises two cavities, each half mould 46A, 46B comprises two half cavities 48A, 49A; 48B, 49B respectively.

Irrespective of the finished shape of the container to be produced, preferably or essentially when the finished shape prohibits easy stripping of the mould (petaloid bottom, for example), each mould associated with means for releasing the containers.

o a1 In thermal conditioning device 3 the preforms are continually spaced at a first pitch P1, where the pitch or the clearance is defined as being the distance separating the longitudinal axis of two adjacent preforms, or similarly, the distance separating the longitudinal axis of the supports of two adjacent preforms in this device. In blow moulding station 40, two adjacent cavities of the same mould are spaced at a second pitch P2, greater that first pitch P1, calculated at a minimum to take into account the radial expansion of the preforms during blow moulding and the necessity of leaving sufficient thickness of material between two cavities so that the mould has correct mechanical resistance during blow moulding. As mentioned previously, the preforms are as close as possible to each other in the thermal conditioning device, and the clearance there is thus less so that the latter is of the smallest size possible, considering the desired overall rate for the plant. As a consequence, interface device 5 comprises means for ensuring modification of the clearance and transfer of the preforms between the thermal conditioning device and blow moulding station By way of example, first pitch P1 can be of the order of 50 millimetres and second pitch P2 can be of the order of 80 millimetres or more. 4UJ P;\OPER\PHH\13446-95.180 -77/98 Figures 2 and 3 illustrate a preferred embodiment of the interface device which is adapted to hold and transfer preforms to the double-cavity blow moulding moulds.

In this particular embodiment, interface device 5 comprises at least two complementary elements: a first element 5A where the preforms arrive at pitch PI, then are separated after stripping from the thermal conditioning device 3 to a second pitch P2, and a second element 5B comprising at least one transfer device for gripping preforms 1 after they have been spaced at the second pitch P2 and for transferring them from the first element into the moulds.

First element 5A is made up of a rotatable platen 51 (designated as a wheel by virtue of its substantially circular shape) provided around its periphery with alternating, fixed elements 52 for holding the preforms, such as slotted scalloped notches, and mobile elements 53 provided with a holding element 54 such as scalloped notches. The clearance between the centres of two adjacent fixed elements 52 is such that the arc of the circle connecting these two elements is of a length which is twice the first pitch P1. As shown in Figure 3, fixed holding elements 52 and mobile elements 54 ensure that the preforms are gripped by a flange 11 located under their neck.

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20 The fixed elements are incorporated directly on the periphery of the platen, in its mass. The platen comprises sectors of reduced thickness which are evenly spaced around its periphery and which define identical radially extending recesses 55 each opening into a space between two adjacent fixed elements 52, while mobile elements 53 are constituted by identical blades, for example of a substantially rectangular shape, each of which is disposed in a respective recess 55. Element 54 for holding the preforms associated with a blade is incorporated at the end of the latter, and the opposite end is rotatably mounted about an axis 56 on platen 51. In addition, axes of rotation 56 of the set of blades are spaced evenly around the platen 51 and delimit a circle concentric to axis of rotation 57 of platen 51. Because of i this arrangement, any rotary movement of a blade about its axis causes a variation in the 30 clearance between associated holding element 54 and the two fixed holding elements 52 i R A.

P;\OPER\PHH\13446-95.180 -7/7/98 -11- located on respective sides of the blade on platen 51. As will be demonstrated hereinbelow, rotation of the blades is performed by control means connected to the blades and to a fixed part of the element 5A such that the angular position of a blade relative to the platen depends, at any given moment of rotation of the platen, on the angular position of the platen relative to the element Ettation of platen 51 about its axis 57, when synchronised with the remainder of the j apparatus is enst;rd by a shaft 58 which receives the rotary movement from a motor, not illustrated here, by way of means known in and of themselves belts, pinions or the like i also not illustrated.

Each blade 53 is connected to a respective crank 59, which is identical for all blades, to ensure its rotation and thus the changing of the pitch. More accurately, first end 60 of the crank connected to a blade is rotatably fixed with an axle defining the axis about which the 15 blade rotates and second end 61 is engaged in a fixed guide cam 62. In the embodiment S illustrated in Figures 2 and 3, cam 62 is constituted by a groove accommodated in the thickness of a fixed platen 63 arranged around drive shaft 58 of rotary platen 51, below the latter and in a plane parallel thereto. The groove foms a closed loop around the shaft and presents variations in its radius of curvature, such that when rotary platen 51 is driven in 20 rotation, tfle second end of each crank follows the variations of the curvature of the groove. Accordingly, each time the second end of a crank encounters a change in the curvature of the groove, the result is rotation of its first end 60, thus the movement of the associated blade and consequently a variation in the spacing between element 54 borne by blade 53 and fixed i holding elements 52 located on respective sides of this blade. Now, since all the blades are i s 25 located and articulated in the same way on the rotary platen (axes of rotation on a circle concentric to the axis of the platen, and identical cranks), they all have identical kinematics, though dephased from one blade to another.

Preferably, as illustrated by Figure 3, which is a view through section AA of Figure I S O 2, second end 61 of each crank is guided in the groove 62 by means of a roller 64 mounted P:\OPER\PHH\13446-95. 180 7n98 -12around this end.

As shown in Figure 3, the thickness of blades 53 and the depth of recesses 55 is such that the fixed notches and the mobile notches carry the preforms at the same level so that they can be introduced at the same level into the moui:s.

In the illustrated example upper plane PL of blades 53 is aligned with upper plane PP of the non-recessed sectors of the platen so that preforms 1 can be held at the same level due to their flange 11 which is located under their neck 12, as much in fixed holding elements 52 as in mobile holding elements 54. i Since the change of pitch cannot occur until after stripping or unloading from the thermal conditioning device 3, it is evident from Figures 2 and 3 that fixed holding elements 52 and mobile holding elements 54 of wheel 51, constituted by the scalloped notches, are not enough to hold the preforms after stripping. For this reason their action is completed by an additional holding elements 66, preferably constituted by a curved guide rail which is effective after stripping and in the zone where the pitch change occurs, up to the point where the preforms are gripped by second element 5B. The clearance between the curved guide rail :and the notches is such that the preforms can slide along the rail when wheel 51 turns, each 20 still being held by their neck between a fixed or mobile notch, in accordance with their *I B r respective position, and the rail 66.

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As previously indicated, interface device 5 comprises complementing pitch-changing element 5A and at least a second element 5B for gripping preforms 1 at the second pitch P2 and transferring them into the moulds. Consequently, if wheel 51 of pitch-changing elerment I turns in the direction shown by arrow 65 in Figure 2, cranks 59 and cam 62 are arranged so that fixed holding elements 52 and mobile holding elements 54 can pass preforms 1 from firtf pitch P1 to second pitch P2 upstream of the zone where second element 5B grips preforms 1.

1 P:\OPER\PHH\13446-95.180 7/7198 -13- As shown in Figure 2, second element 5B comprises at least one transfer element 67, 68, 69. By virtue of the increased rates of the plant several identical elements are preferably present. In the example shown in Figure 2, there are three elements.

Each element comprises an arm 70 having a first end, on which is rotatably articulated, by a pivot 71, a support 72 carrying the samne number of pairs of pincers 73, 74 as each carousel mould 4 has mould cavities. Therefore, in the embodiment shown in figure A 2, each arm supports two pairs of pincers, the centres of which are separated by second pitch P2.

t Preferably, each pair of pincers is constituted in the same way as those found in known plants comprising a single mould cavity, that is, they may be pairs of pincers whose openings and closing is controlled by a system of cams, rollers and springs, or more simply, as in the embodiment illustrated in Figure 2, pairs of pincers having springs which open due 15 to the force exerted by the neck of the preforms, just when the preforms are introduced or j extracted from them, and which close under the action of the springs which connect them to i their support. These two types of pairs of pincers are well known and will not be described in any further detail.

The second end of arm 70 is mounted for rotation and translation on a support itself turning about an axis 750 in synchronicity with the remainder of the plant. The rotation and translation movements of the second end of the arm are ensured, in a known manner, by fixed cams 76, 77 relative to the plant, driving rollers being connected to the arm and guided by these cams.

This arrangement is made especially so that when the preforms are gripped, the movement of the first end of the arm is controlled by rotation of the platen 51, effectively |i allowing the first end, and thus the pincers, to accompany the platen over a sufficient distance to ensure a perfect grip.

l P:\OPER\PHH\ 3446-95.180 717/98 S14 This arrangement is also made so that a second automatic control between the movement of the first end of the arm and a die support takes place during transfer of the preforms into the cavities of the mould, ensuring perfect positioning of the preforms in the cavities.

Furthermore, the variation in the length of the arms, permitted by the movements of rotation and translation, allows optimisation of the spatial requirement of these arms during rotation between the moment of gripping and the moment of transfer.

However, given that each arm bears at least two pincers, it is possible that the sole i automatic control of the first end of arm 70 is not enough to ensure gripping of the preforms on the pitch-changing wheel 51 or correct transfer of the preforms into the moulds. This is why the movements of rotation and translation of the arm are accompanied by rotation of a i support 72 of the pairs of pincers relative to this arm, permitting correct positioning of the 15 pincers, and accompanying the movement provided as much by the platen during gripping of the preforms as by the moulds during transfer and their closure.

This rotation of support 72 of the pincers is generated by a third cam 78 which is fixed S-. relative to rotary support 75, which in turn drives another roller 79 connected to a first end 20 of a first connection rod 80, whose second end is connected to support 72 of the pincers, and by a second connecting rod 81 connecting roller 79 to a second end of arm Figure 2 shows one of the three transfer arms in a mould 41.

The end of the guide rail 66, complementing the fixed or mobile notches, is preferably extended by a mobile part 82 which retracts after the preforms have been gripped by the pincers to allow more rapid disengagement of the preforms and to avoid having to prolong the accompanying movement of the platen until the last preform being gripped is completely disengaged from the rail. In the embodiment illustrated, this mobile part 82 is a portion of 1 RAr-O0 curved rail rotatably mounted on complementary guide rail 66. When the pincers connected P:\OPER\PHH\13446-95.180 7/7/98 to an arm have yet to grip the preforms, mobile part 82 extends the complementary rail 66.

As soon as gripping takes place, mobile part 82 moves away.

A cam groove 83 turning synchronously with the plant drives a connecting rod 84 which is connected to mobile part 82. The profile of the cam groove is such that mobile part 82 remains in a position holding the preforms before gripping, then moves away after gripping and returns to the closed position until the next preforms are gripped.

After blow moulding in the moulds, containers 13 are released with the assistance of a device 5C which comprises one or more transfer elements having a structure similar to that of elements 67, 68, 69 which load the preforms. These elements comprise one or more arms 86, 87 each of which is mounted for rotation and translation about a single support 88, itself revolving around an axis 880; articulated to each arm is a support 89, 90, 91 with as many gripping means, such as pair of pincers, as there are mould cavities in each mould. The 15 pincers grip containers 13 by their neck in known fashion.

A mechanism having cams 881, 882, rollers and connecting rods 890, 900, 910 allows the movement of the pincers to be coordinated with rotation of a mould to enable the orientation necessary for good gripping of the containers, and with a wheel 52 to allow the containers to be released. The wheel 92 has peripheral notches 93, and a support 94 in the shape of a curved rail is complementary to the notched wheel.

SAn element 95 in the form of a short curved guide preferable extends complementary support 94. This element is connected to a mechanism having a cam 96, a roller 97 and connecting rod 98, of which the cam is driven synchronously with the remainder of the plant.

Element 95 disengages under the action of the mechanism of cam 96, roller 97 and connecting rod 98 at the very time when the pincers arrive at the notched wheel and draws near when the containers are received in the notches to facilitate gripping of the containers by the notched i wheel. The;, containers, guided by their necks between the nieched wheel and the "I .i complementary element 95, are then extracted against the force of the pincers while the i 1 P:\OPER\PHH\1344695.180 7/98 -16transfer element continues to rotate in a crosswise direction.

Figure 4 illustrates a preferred lay-out of the elements in Figures 2 and 3, where thermal conditioning device 3 is of the linear type, that is, in which endless reel chain 31, of known structure, has at least two linear sectors accommodating heating zones 32 and is held between two platens or wheels, the first of which 99 serves to drive this chain synchronously with the remainder of the plant, and a second 100 serves to tension and returns the chain. A In this case, pitch-changing device 5A, constituted by the variable pitch notched wheel 51 of Figure 2, is arranged coaxially to first platen 99 for driving reel chain 31, underneath i the latter, and is driven along with it. As explained hereinafter, this arrangement enables this variable pitch wheel 51 to be used for loading onto and unloading the preforms from the reel chain 31. i In Figure 4 first platen 99 is showing in a cutaway view so that the variable pitch t"o: notched wheel 51 can also be seen.

Assuming that thermal conditioning device 3 is driven in the direction indicated by arrow 101, supply device 2 directs preforms 1, with their openings facing upwards, to a point 20 in zone ZP1 of the plant where the pitch between fixed notches 52 and mobile notches 54 of the wheel 51 is first pitch P1, the same as the pitch in thermal conditioning device 3. The i first platen 99 is also notched. Each notch and thus each preform supported on whel 51 in this zone ZP1 cooperates with a respective support means of the reel chain 31, each of which comprises, for example, a mandrel and an elastic ring and is rotatable.

Each preform delivered by the supply device is received in a fixed or mobile notch 52 or 54, then steered towards a loading device 102 by known means such as a device with cams S (not illustrated) which causes the mandrel and the elastic ring associated with each support 'i device to be lowered into the neck of the preforms. ir

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P;\OPER\PHiH\I3446-95,180 7/798 -17- Next, the preforms pass into a zone 103 where they are upturned so that their base now faces upwards in heating zones 32.

Following thermal conditioning and before arriving back on wheel 51 with fixed notches 52 and mobile notches 54, the reels are again upturned by a device 104, also known, so that the preforms now have their base facing downwards.

Then in a zone 105 while still in zone ZP1 where the pitch between t w is first pitch P1 after being located between a notch and the complementary holdii, element 66, constituted in Figure 2 by a portion of curved rail, each preform is subjected to unloading by disengagement of the mandrel and elastic ring. Each preform is then carried solely by its neck between a notch and the complementary holding element 66.

The preforms then enter a zone ZP2 where they undergo changing of pitch before being gripped by the second element 5B comprising the at least one transfer device for gripping the preforms and conveying them to the moulds.

*o The result of the above is that with this particular embodiment cam 62 guiding cranks 59 must be profiled so that the holding elements, such as fixed or mobile notches, are at first S 20 pitch P1 at least during loading onto and unloading from the reel chain 31.

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4 i Furthermore, this cam must be profiled such that the holding elements are at second pitch P2 at least when pincers 73, 74 of the device fpr transferring the preforms towards the moulds are in contact with the preforms.

On the contrary, it is unnecessary, though preferable, for the cam to be profiled so that the preforms are supplied to a zone where the holding elements are at first pitch Pl; in fact, it is quite conceivable that the preforms are supplied to a zone where the pitch is second pitch P2, while pitch P1 is returned to between the moment when the preforms are clamped i4 0 by a notch and are engaged with the support means of the reel chain 31.

R 1 SO Z PA\OPER\PHH\13446-95.180- 7/7/9s -18- In a variation, not illustrated, supply de i of the preforms steers the preforms, not directly on pitch-changing wheel 51, but on ao: ,,ilediate loading path.

Figure 5 illustrates a possible lay-ort ot rhe elements of Figures 2 and 3 in an installation in which the thermal conditioning device is a carousel 106.

The means of supplying, loading and conditioning are known means. Therefore, supply device 2 steers preforms 1 onto an intermediate wheel 107 with notches 108 and onto a support 109 in the form of a curved guide rail. Each preform, carried by its flange 11 by a notch 108 and support 109, is steered towards a loading zone 110, then to an upturning zone i 111, preceding thermal conditioning zones 32.

After thermal conditioning, the preforms are again upturned in a zone 112, then are unloaded at 113 immediately before being clamped between notches 114 of another 15 intermediate wheel 115 and a support 116 in the shape of a curved guide rail.

Wheel 51 with fixed notches 52 and mobile notches 54 as well as complementary holding element 66, constituted by a curved guide rail, are located immediately downstream of intermediate wheel 115 and support 116, such that the preforms, guided between notches 20 114 of this wheel 51 and support 116, can be transferred from this wheel and from this support between fixed notches 52 and mobile notches 54 and complementary holding element 66 in order to make the change in pitch.

Downstream of wheel 51 with fixed and mobile notches is second element 5B for gripping preforms 1 after they have been set at second pitch P2 and for transferring them into the moulds.

Of course, the invention is in no way limited to the embodiments described herein, razter it includes their equivalents and all the variations or adaptations which would be within i 0the scope of the claims.

1 *jp^ f8 LI P;\OPER\PHH\1344695.180 -7/798 -19- Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

DATED this SEVENTH day of JULY, 1998.

SIDEL S.A.

by DAVIES COLLISON CAVE Patent Attorneys for the Applicant(s) 'p *c 9 *909 we 49

I

1: ii.

Claims (18)

1. Apparatus for the production of containers by blow moulding preforrns, comprising at least two portfolio moulds arranged on the periphery of a blow moulding carousel, each of the moulds having at least two moulding cavities whose longitudinal axes are spaced apart by a first distance, wherein the apparatus furthe!r includes drive means for transporting and holding the preforms on a path along which thermal conditioning means is 'disposed and in which the spacing between the longitudinal axes of adjacent preforms is a second distance less than the first distance, means for transferring the preforms to a mould, and means for modifying the spacing of the preforms between the drive means and the mould. 00::2. Apparatus as claimed in claim 1, wherein said first distance is calculated based on the radial expansion of the preforms during the blow moulding operation, and a thickness of material to be left between said at least two moulding cavities sufficient to ensure that the mold has the proper mechanical strength during the blow-moulding operation.

3. Apaau*scamdi0lam1o li ,weenth pcn oiyn en 3. Apparatus as claimed in claim 13rca2 wherein the men o rsacing mifigsess pfor transferg trans fergip adjacent preforms o the spacing modifying means tona for placing them in the at least two moulding cavities. Apparatus as claimed in claim 3 or claim 4, wherein the sparing modifying means comprises a rotatable plate incorporating alternating fixed and movable means for receiving v the preforms.

6. Apparatus as claimed in claim, 5 wherein the fixed and movable means comprise P:\OPER\PHHUI3446-95.180 -20 1/98 V -21- notches for receiving preforms, and wherein the apparatus further includes a curved guide allowing the preforms to be carried by the rotating plate between the notches and the curved guide from when these are unloaded from the drive means to when they are received by the means for transferring.

7. Apparatus as claimed in claim 7 wherein the rotatable plate is circular and the fixed notches are spaced evenly about the periphery of the plate and made directly in the mass of the plate.

8. Apparatus as claimed in claim 6 or 7, wherein the movable notches are formed in identical elements which are mounted rotatably on the plate and means is provided whereby, at any time, the position of any one of the movable elements relative to the fixed notches on either side thereof is dependant on the angular position of the rotatable plate.

9. Apparatus as claimed in claim 8, wherein the rotatable plate comprises sectors which are spaced evenly apart and which define identical radially extending recesses each 0 accornmmodated in a space between two adjacent fixed notches, the movable elements being located in the recesses such that the fixed and movable notches transport the preforms at the same level. Apparatus as claimed in claim 8 or 9, wherein the axes of rotation of the movable elements are spaced evenly around the rotatable plate and delimit a circle concentric to the axis of rotation of the plate.

11. Plant as claimed in any one of claims 8 to 10 wherein each movable element is connected to a respective crank to ensure its rotation and thus the changing of the spacing, with a first end of each crank connected to a respective movable element being rotably connected with a rotatable axle of the movable element and a second end being engaged in a guide cam provided; "lie spacing modifying means. P:\OPERIPHH\13446-95 180-2/11/98 22

12. Apparatus as claimed in claim 11 wherein the guide cam is constituted by a groove forming a closed loop in a stationary plate disposed around a drive shaft of the rotatable plate in a plane parallel to the latter, the groove having variations in its radius of curvature such that when the rotatable plate is rotated, the second end of each crank follows the variations of the curvature of the groove, actuating rotation of the associated crank and thus a variation in the clearance.

13. Apparatus as claimed in claim 4 or any claim dependent therefrom, wherein the first preform-transfer means for gripping the preforms, such as pairs of pincers, as each mould has 10 moulding cavities, the spacing between the centres of adjacent gripping means being identical to the first distance. Poo

14. Apparatus as claimed in any one of claims 1 to 13, which includes second transfer means for unloading the containers from the moulds. 1 15. Apparatus as claimed in claim 14, wherein the second transfer means comprises at least one second arm of which a first end carries the same number of means for gripping the Scontainers, such as pairs of pincers, as each mould has moulding cavities, the spacing between the centres of adjacent gripping means being identical to the first distance.

16. Apparatus as claimed in claim 13 or 15, wherein the gripping means for the preforms are carried by a first support rotatable mounted on the first end of the first arm of the first preform-transfer means and/or the gripping means for the containers are carried by a second support rotatably mounted on a first end of the second arm of the second transfer means.

17. Apparatus as claimed in claim 16, wherein a second end of the first arm is mounted on a third support rotatable about an axis parallel to that of the carousel carrying the moulds and/or a second end of the second arm is mounted on a fourth support rotatable about an axis parallel to that of the carousel carrying the moulds, and wherein means is provided for the 0 first and/or s!.icond arm to perform movements of rotation and translation relative to the p -P:\OPER\Ph14\3446&95.180 -20/11/98 23 respective third or fourth rotatable support.

18. Apparatus as claimed in claim 17, wherein movements of rotation and translation of the first support of the gripping means for the preforms and/or of the second support of the gripping means for the containers, at the iirst end of the first and/or of the second arm, respectively, are controlled by means connected with the respective third or fourth rotatable support.

19. Ap.,paratus as claimed in claim 17 or 18, wherein the means for the first and/or second 10 arm to perform the movements of rotation and translation relative to the respective third or fourth rotatable support and/or means for the first or second rotatable support of" each gripping means to perform. the movements of rotation and translation relative to its respective arm comprise cams carried by the respective third or fourth rotatable support and acting on *:Got: complementary elements, such as rollers and connecting rods, connected with the respective arm. Apparatus as claimed in claim 5 or any claims dependent therefrom, wherein the drive means associated with the thermal conditioning means comprises an endless chain of preform 20support devices extending between two wheels, and wherein the rotatable plate of the spacing means is arranged below one of the wheels coaxially therewith, is driven therewith, and is adapted to be used to support the preforms while they are engaged with the preformp support devices and/or between the unloading of the preforms from the drive means and the engagement of the preforms by the means for transferring.

21. Apparatus as claimed in claim 20, wherein the spacing-modifying means are arranged so that the fixed and movable means for holding the preforms are spaced by the second distance when they'are in a zone for engaging preforms with the preform support devices and/or when they are in a zone for unloading the preforms from the drive means. P:\OPER\PHH\13446-95.180 -20/f1/98 -24- therefrom, wherein the means is part-circular and the drive means associated therewith comprises an array of preform support devices carried with the rotatable plate of the spacing modifying means disposed at the periphery of the carousel so as to engage and support the preforms after they are unloaded from the drive means and until thy are engaged by the means for transferring.

23. Apparatus for the production of containers by btow moulding preforms, substantially as herein described with reference to the accompanying drawings. 0 0, '04 60 0 0. a %D 0#004 555,O SRSR S *I S S 54 *S SI 55 8* a SC* *r A

24. A plant substantially as hereinbefore described with reference to the drawings.

25. The steps, features, corrmpositions and compounds disclosed herein or referred to or indicated in the specification and/or claims of this application, individually or collectively, and any and all combinations of any two or more of said steps or features. .4 DATED this 20th day of NOVEMBER, 1998 Sidel S.A. by DAVIES COLLISON CAVE Patent Attorneys for the Applicant(s) .X